grread function returns raw user
input, whether from the keyboard or from the pointing device (mouse
or digitizer). If the call to grread enables tracking, the
function returns a digitized coordinate that can be used for things
such as dragging.
NoteThere is no
guarantee that applications calling grread will be upward compatible.
Because it depends on the current hardware configuration,
applications that call grread are not likely to work in
the same way on all configurations.